An assessment of the fibrinolytic system in hemophilia A

The fibrinolytic system was assessed in 28 hemophiliacs using the chromogenic substrate H‐D‐Val‐Leu‐Lys‐pNA. To determine whether a state of hyperfibrinolysis might be associated with Factor VIII replacement therapy, 14 patients with severe disease who were intensively treated with Factor VIII concentrates were compared with 14 patients with mild disease who were receiving infrequent transfusions with cryoprecipitate or fresh frozen plasma. Seventeen normal males served as controls. With the exception of an elevated level of plasminogen activator and a decreased level of immediate antiplasmin in the mild group only, no evidence of enhanced fibrinolysis was found. Other components of the fibrinolytic system were either normal (plasmin) or increased (progressive antiplasmin containng both α₂PI and α₂M, and plasminogen). The elevated plasminogen levels were found only in the severe intensively transfused group. The elevated progressive antiplasmin levels were found in both groups of patients and did not appear to be related to transfusions. These findings do not support the concept of enhanced fibrinolysis associated with intensive Factor VIII replacement therapy.